Copyrights of digital content can be protected through the use of watermarks. Watermark detection, however, faces one major technical challenge. Existing detection mechanisms require the knowledge of a detection key, which may also be used for watermark removal. Due to the issues of performance and scalability, watermark detection is often offline and realized at the user's end. This makes the detection mechanism vulnerable to attacks and thereby jeopardizes the confidentiality of detection keys. As such, mechanisms of copyright protection may not rely on the robustness of watermarks. In this thesis, we propose an offline mechanism to reinforce copyright protection for situations where watermark robustness cannot be guaranteed. On purchasing a piece of digital content, a consumer receiv...[ Read more ]

Copyrights of digital content can be protected through the use of watermarks. Watermark detection, however, faces one major technical challenge. Existing detection mechanisms require the knowledge of a detection key, which may also be used for watermark removal. Due to the issues of performance and scalability, watermark detection is often offline and realized at the user's end. This makes the detection mechanism vulnerable to attacks and thereby jeopardizes the confidentiality of detection keys. As such, mechanisms of copyright protection may not rely on the robustness of watermarks. In this thesis, we propose an offline mechanism to reinforce copyright protection for situations where watermark robustness cannot be guaranteed. On purchasing a piece of digital content, a consumer receives a unique license in a signed license from the associated content distributor. The license will be used for checking the rights of the consumer as well as the genuineness of the watermarks. The integrity of licenses is protected by the public key infrastructure (PKI).